Method and apparatus for loosening windings of a coil prior to heat treatment



06L 1964 H. J. KIRSCHNlNG ETAL 3,154,299

METHOD AND APPARATUS FOR LOOSENING WINDINGS OF A con. PRIOR To HEATTREATMENT Filed June 50, 1961 R S. 6 m F m ca a 0 N M 6 f. H M F %E 555C RK 4 RT 6 M 5 Wu V MM 0 a m M mm MS \\\Y m m mm mm a l 5 w M M% pic 0R A 5 0 6 M a a u 6 4 h \Qv 3M x W u /1? 6 v. 5 ll. I A //X/ c w. B w Ay PL A 7'FORM axe/v: M070? nssewuy BY 7 w? ,W/W

ATTORNEYS United States Patent 3,154,292 METHQD AND APPAPATTE FGR L@@EP-ENG WLQDZNGd SF A C011 Ti} HEAT Hans Joachim l schning, Duisburg, andHeinrich Schwenlre, @snahrue" hausen, Germany, assignors to Kloci-znereAG, Duisburg, Germany, a corporation of Germany Filed June 30, 1961,Ser. No. 121,149 Claims priority, application Germany, .iuly 7, 1960, K4Ll33 19 Claims. (Cl. 263-4 1l) The present invention concerns a methodfor the loosening of tightly wound windings of a coil to be annealed orheat treated under a heating hood, i.e., in a heat treatment furnace, aswell as apparatus to carry out the method.

It is known that due to cold working of strip steel, such as takes placeduring cold rolling, the internal structure of the material is changedand it becomes strain hardened. Strain hardening of the material isundesirable in many instances. This hardening is, therefore, eliminatedby a re-crystallizing, annealing process, in the course of which theoriginal strength of the material is reconstituted. At the same time, bythe action of protective gases, an improvement of the surface of thestrip steel is achieved.

In the case of a tightly wound coil in which the windings are tightlycompressed, a prolonged heating time is necessary for the heat topenetrate from the outside into the interior of the coil in order toreach the re-crystallization temperature. This drawback, namely, theprolonged time required to heat the coil, to hold it at an annealingtemperature and to cool it, has been previously overcome, as is wellknown, by winding up, together with the steel strip, a thread on aseparately installed winding machine. After completion of the windingprocess, the thread is pulled out and the now loose packing density ofthe coil permits free access of the protective gases in the furnace andallows heat to reach the individual windings of the coil. A disadvantageof this method is the requirement for a second, separate winding deviceon which both thread and strip steel are wound up together. Thesubsequent transfer of the thus loosened coil into the furnace must beaccomplished in such a way that there is no dislocation of the windingswith respect to the existing diameter of the coil. Technically, this ismade possible by using lifting magnets, though the chance of damagingthe edges of the loosened coil cannot be eliminated entirely.

The method, according to this invention, avoids this mentioneddisadvantage in that a rotary movement of the coil relative to asupporting plate for the coil is provided in which the axis of movementcoincides with the axis of the coil.

Specifically, each end of the coil is moved at a difierent angularvelocity about the axis of the coil so that the relative angularvelocity of the ends is in a direction to enlarge their diameter,thereby producing the loosening action.

The actual loosening process is performed most advantageously in thehood-type annealing furnace and, contrary to methods used so far, theprocess is carried out, not on a winder, but on a rotating coilsupporting plate, which can be a component part of the annealingfurnace. Of course, it is also possible to perform the loosening processoutside of the annealing furnace.

According to a further development of the method, according to theinvention, both ends of the strip of the coil are rotated relative toeach other to loosen the windings by fastening the ends to suitableoperating parts.

This present invention deals also with devices that carry out the abovedescribed method. According to one type of apparatus, a central spindle,around which the core ice is wound, penetrates the center of asupporting plate on which the wound coil rests, the plate in turn beingprovided with openings for the gas to pass through. These units arerotated, preferably in a steady and uniform rotary movement. Acylindrical casing or shell can be provided around the supporting plateand it, in turn, is rotated in an opposite direction to the spindle andthe supporting plate.

For all parts of the device, i.e., for the casing, the supporting plateand the spindle, separate drives can be provided in order to enable anoptimum rotary movement of these parts to most effectively accomplishthe loosening process.

The present invention is explained by means of the enclosed drawingwherein FIG. 1 is a vertical cross-sectional view of an apparatusillustrating the principles of the invention and FIG. 2 is a top planview of an apparatus incorporating the invention. As is apparent,certain conventional units are diagrammatically illustrated.

Coil 1, with spindle 2 at its center, is placed on the supporting plate3 with the inner end of coil 1 connected to spindle 2, as indicated atB. The outer end of coil 1 is connected to the circular casing 4, asindicated at A. The process for loosening the tightly compressedwindings is carried out by rotating spindle 2 and support plate 3 in onedirection, as indicated by the arrows in FIG. 2, for example, and thecasing 4 in the opposite direction. The turns of coil 1, moving acrossthe surface of support 3, will move very quickly into the clearance 5between the coil and the casing. After continued rotation, the outerturn of the coil will press against the interior surface of the outercasing 4 The drive assemblies 6, 7 and 8, which rotate the spindle 2,supporting plate 3 and easing 4 are preferably arranged in such a waythat the rotational speeds of shaft 2 and of the supporting plate 3 areidentical. Openings 9 extend through supporting plate 3 as shown in thedrawing to permit gas to be fed to the coil from a source of treatinggas diagrammatically illustrated at 10.

While We have described and illustrated an embodiment of our invention,we wish it to be understood that we do not intend to be restrictedsolely thereto but that we do intend to cover all modifications of ourinvention which would be apparent to one skilled in the art and whichcome within the spirit and scope of our invention.

We claim:

1. The method of heat treating a strip of metal tightly wound into acoil, comprising the steps of supporting the coil on one of its ends ona horizontal platform, causing relative rotation of the ends of saidcoil relative to said platform while said coil is subjected to a thermalcondition.

2. A method of heat treating a tightly wound metal coil comprising thesteps of vertically supporting the coil on one of its ends on aperforated horizontal surface, effecting relative horizontal movement ofsuccessive outer convolutions of the coil by rotating said coil relativeto said horizontal surface and about the axis of said coil, and xposingthe said successive convolutions of said coil to a heating gas passingthrough the perforations of said horizontal surface.

3. A method for loosening the tightly wound turns of a coil to beannealed in a heating apparatus, said method comprising the steps ofvertically supporting the coil on one of its ends on a supporting plate,driving the coil in a rotary direction by an external force about itsaxis and relative to said coil supporting plate in a direction whichopens the turns of the coil and passing a heating gas through andbetween the opened turns of the coil.

4. A method according to claim 3 wherein the inner and outer ends of thecoil are separately driven by external forces in opposite directions.

5. A method of heat treating a strip wound into a tight coil comprisingthe steps of loosening the turns of said coil by separately driving theinner and outer ends of the coil about the central axis of the coil atrespective relative angular velocities which reduce the number of turnsand cause adjacent turns to be spaced apart, and then subjecting thecoil to a thermal condition by passing a heating gas through and betweenthe spaced turns which heats said spaced turns to a required temperaturefor a predetermined time.

6. In a method of heat treating a. coil which has been tightly wound,the step of loosening the tightly wound turns by separately driving theinner and outer ends, respectively, of the coil about the coil axis atangular velocities producing a relative angular velocity between saidends in a direction which reduces the number of turns in the coil,thereby loosening the turns, with open spaces therebetween, to exposethe surfaces of said turns, and applying directly to the said exposedsurfaces of said turns a heat treating atmosphere.

7. An apparatus for loosening the turns of a tightly wound coil andsupporting said coil in a heat treating furnace after being loosenedcomprising a first member having means attaching to the inner end ofsaid coil, a second member located relative to said first member to beengageable with the outer portion of a said coil attached to said firstmember, said members mounted to rotate relative to each other about theaxis of said coil attached thereto, and means connecting to a least oneof said members to rotate said first member relative to said secondmembers, whereby the turns of said tightly wound coil are loosened bythe relative movement between the inner and outer portions of the coil.

8. An apparatus for loosening the turns of a tightly 'WOIlIld coil priorto heat treatment and holding the loosened coil during heat treatmentcomprising a coil support plate mounted for rotation about its center,means connected to said support plate to rotate said support plate, anaxially rotatable spindle mounted perpendicularly adjacent to the centerof said support plate and rotatable relative to said support plate,means adapted for attaching said spindle to the inner end of a coilconcentrically located around the spindle, and means connecting to saidspindle to rotate said spindle, whereby the relative motion between saidspindle and support plate increases the diameter of the turns of a coilmounted thereon and loosens said turns.

9. An apparatus for loosening the turns of a tightly wound coil prior toheat treatment and holding the loosened coil during heat treatmentcomprising a support plate mounted for rotation about its center tosupport the face of said coil, said support plate having transverseopenings, a spindle mounted perpendicularly adjacent to said plate atsaid center for separate, axial rotation and having means adapted forattaching to the inner end of said coil, an unwinding member mounted forrotation around the axis of said spindle and having means adapted forattaching to the outer end of a said coil concentrically located aroundsaid spindle, and means rotating said outer member relative to saidsupport plate and spindle, whereby the relative motion between saidouter member and said support plate and spindle increases the diameterof the turns of a coil mounted thereon and loosens said turns.

10. In a heat treating furnace for heat treating a tightly Wound coil,the combination of a support plate mounted within said furnace forrotation about its center to provide a support for the face of saidcoil, said support plate having openings to permit furnace gases to passthrough, a spindle mounted perpendicularly to and piercing said supportplate at its center for separate,

axial rotation and having means adapted for attaching to the inner endof said coil, an annular casing with an inner diameter adapted to belarger than said coil mounted within said furnace for separate rotationconcentric to said spindle and having means adapted for attaching to theouter end of a said coil concentrically located around said spindle,means connecting to said casing to rotate said casing in one direction,and separate means connecting to each of said spindle and said supportplate to rotate said spindle and support plate in the opposite directionat a uniform rate, whereby the relative movement between said casing andsaid spindle and support plate increase the diameter of the turns of acoil placed within said furnace on said support plate and concentricallylocated around said spindle within said casing and attached theretoloosen said turns and open spaces therebetween prior to the heattreating operation, thereby exposing the surfaces of each turn to theheat and gases within the furnace.

References Cited in the file of this patent UNiTED STATES PATENTS

1. THE METHOD OF HEAT TREATING A STRIP OF METAL TIGHTLY WOUND INTO ACOIL, COMPRISING THE STEPS OF SUPPORTING THE COIL ON ONE OF ITS ENDS ONA HORIZONTAL PLATFORM, CAUSING RELATIVE ROTATION OF THE ENDS OF SAIDCOIL RELATIVE TO SAID PLATFORM WHILE SAID COIL IS SUBJECTED TO A THERMALCONDITION.